Néel-Vector Control of the Josephson Diode Effect in 𝒫𝒯-symmetric Antiferromagnets

@misc{xu2026néelvector,
  title = {{Néel-Vector Control of the Josephson Diode Effect in $\mathcalPT$-symmetric Antiferromagnets}},
  author = {Xian-Tang Xu and Xun-Jiang Luo and Mingliang Tian and Ning Hao},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.08278},
  eprint = {2609.08278},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.08278},
}

TY  - UNPB
TI  - Néel-Vector Control of the Josephson Diode Effect in 𝒫𝒯-symmetric Antiferromagnets
AU  - Xian-Tang Xu
AU  - Xun-Jiang Luo
AU  - Mingliang Tian
AU  - Ning Hao
PY  - 2026
DA  - 2026/09/20
PB  - arXiv
DO  - 10.48550/arxiv.2609.08278
UR  - https://arxiv.org/abs/2609.08278
AB  - The interplay of superconductivity and magnetism gives rise to rich phenomena in Josephson junctions. In this Letter, we study Josephson junctions formed by conventional s-wave superconductors and a PT-symmetric collinear antiferromagnet modeled on CuMnAs. Using microscopic modeling and symmetry analysis, we show that these junctions exhibit both the Josephson diode effect and φ_0-junction states. Remarkably, both effects are controlled by the Néel vector: rotating it by 90^∘ switches off both, while reversing it switches the diode polarity. To reveal the microscopic mechanism, we develop a channel-resolved scattering theory that accurately captures the anomalous phases and establishes the exact condition for the diode effect. The interplay of the channel current-phase relations yields a sizable diode efficiency, tunable by both the magnitude and direction of the exchange field. Furthermore, a Green-function reduction identifies a single renormalized PT-degenerate band as the transport carrier and precisely reproduces the full current amplitudes. Our work establishes PT-symmetric antiferromagnets as versatile platforms for field-free, highly tunable Josephson diodes and φ_0 junctions.
ER  -